Some water-themed amusement rides have introduced the concept of propelling riders, objects, or passengers along conduits, chutes, or channels (used interchangeably). Some rides propel riders by creating a primary flow or stream of water within the conduit or chute. Such a stream must be strong enough to sustain the motion of a desired range of riders over a predetermined length of conduit. For example, a ride might include an initial decline, followed by a level portion leading to a second decline. In such case, the stream is maintained by the conversion of potential energy into kinetic energy, with the kinetic energy at the bottom of the first decline sufficient to propel the rider to the second decline. The rider may be directly within the stream, or floating on the stream with a pad, mat, small boat, float, or other such object.
In another example, riders may be propelled by one or more waterjets situated within a portion of the conduit or channel. The jet is oriented so as to impart momentum to the rider along a desired direction within the conduit. In this way, the primary stream may be reduced or even omitted, with the one or more propelling streams or jets moving the rider along. In this approach, the waterjets have been successfully implemented in rides that include inclines as well as level conduit and declining conduit.
As discussed in U.S. Pat. No. 5,503,597, the waterjets may be operated by using the pressure generated from a pump or an elevated reservoir. Nozzle pressure was disclosed as ranging from 5 to 250 psi, with a preferred range of 15-25 psi. While various configurations of piping have been implemented and disclosed, these conventional embodiments have largely been implemented with electric motor driven impeller pumps within the system. Some versions supply nozzles from the discharge of such pumps. Other versions include an elevated reservoir or tank, which may then be supplied by such pumps.
The input power Pi required by a pump is generally a function of the energy imparted (H, potential energy, or head) to the water and the flow rate Q of the water, with the remaining inputs being constants associated with water property or pump efficiency:
      P    i    =            ρ      ⁢                          ⁢      gHQ        η  Flow rate and energy are set by the needs of the water ride design, and the specific conduit configuration. For example, higher and longer portions of conduit would generally require more power than lower, shorter portions. Experience has shown that many of these embodiments face high energy costs for such waterjets, with one example in the year 2013 having energy cost of $150,000 to $200,000 for that single season of operation.
This high rate of energy consumption persists despite the use of motion detection sensors to time the opening of solenoid valves to release the jetted water needed for a particular rider. While the motion sensors and solenoid valves can reduce the volume of water discharged, and possibly the decrease in pressure, there is little overall reduction in energy due to operational constraints.
The approach in U.S. Pat. No. 5,503,597 requires the maintenance of water at pressure. The electric motor driven pumps are reactive loads that consume additional power and current during startup, as the rotors and pump accelerate to operational levels. Shutting pumps down between riders would increase the overall power consumed. In addition, for many embodiments the pumps must be in an operational status to be available for the next rider. Shutting the pumps down between riders would introduce potential delays, given the time needed to start up the pumps. With the increase in power consumption during start up, multiple pumps are often started sequentially to spread out power demand. Cycling the pumps may introduce additional wear, and would require additional attention from operators.
Accordingly, there is a need for a system and method with a reduced energy costs.